<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
  <script src="../js/vue.js"></script>
</head>
<body>

<div id="app">
  <h2>{{message}},test</h2>
  <h2>{{firstName+lastName}}</h2>
  <h2>{{firstName+" " + lastName}}</h2>
  <h2>{{firstName}}  {{lastName}}</h2>
  <h2>{{counter*2}}</h2>
</div>

<script>
  const app = new Vue({
    el:'#app',
    data:{
      message:"message",
      firstName:'xiao',
      lastName:'liang',
      counter :100

    },
    methods:{

    }

  })
</script>

</body>
</html>